PSI - Issue 81

Roman Samchuk et al. / Procedia Structural Integrity 81 (2026) 184–191

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verification is typically performed using a nominal- stress S–N approach with standardized fatigue detail categories and simplified action models. In the Eurocode framework, the fatigue assessment of crane supporting structures is covered in EN 1993-6 (2007) together with fatigue resistance rules from EN 1993-1-9 (2005). EN 1993-6 (2007) states that fatigue assessment is generally required for components subject to stress variations from vertical crane loads, while stress variations from horizontal crane loads are normally negligible, while pointing to possible exceptions for some types of crane support ing structures and crane operations (e.g., surge connections due to lateral loads and fatigue e ff ects caused by multiple acceleration and braking actions). This combination of statements may be interpreted in practice as permission to ignore horizontal actions by default, unless a special case is obvious. At the same time, EN 1991-3 (2006) provides actions induced by hoists and cranes on runway beams and specifies that operational conditions and variation of crane positions should be considered in fatigue loading. It also indicates that, when su ffi cient project information is available, fatigue loads may be determined according to EN 13001 and EN 1993-1-9 (2005), and that the methods are compatible with EN 13001-1 (2015) and NEN-EN 13001-2 (2021) to facilitate data exchange between crane suppliers and runway designers. On the other hand, EN 1991-3 (2006) allows us to express fatigue loads in terms of equivalent fatigue damage loads Q e , which may be taken as constant for all crane positions to determine fatigue load e ff ects. In this simplified approach, the damage-equivalent wheel load is commonly expressed as The key observation is that Eq. (1) anchors the fatigue action representation to the vertical wheel load; therefore, if cyclic horizontal actions from travel drives are not introduced separately, their fatigue contribution is omitted by construction. These provisions motivate a closer look at whether a simplified “vertical-only” fatigue representation is consistently safe for typical operational scenarios, since such a shortcut may be seriously misleading for fatigue assessment. Horizontal actions are an integral part of the operational cycle due to the repeated acceleration and braking of the crane and trolley travel. These cyclic actions can be transferred through the rail into the runway girder and may contribute to stress ranges at fatigue-critical welded details, especially when the rail is rigidly attached and the global sti ff ness enforces a distinct load path. Objective and contribution. The objective of this paper is to quantify, by means of a realistic numerical case study, how cyclic horizontal crane actions influence fatigue damage at the welded web–flange connection of a steel runway beam. A detailed shell finite-element model of the crane and runway system is combined with fatigue checks based on EN 13001 and the Eurocode fatigue framework. Two verification scenarios are compared: Scenario V (vertical only) and Scenario VH (combined vertical + horizontal) actions. A comparative fatigue assessment is carried out for di ff erent weld detail classifications (double fillet vs full-penetration) and for EN 13001 vs Eurocode. Q max , i maximum characteristic vertical wheel load for wheel i Q e damage-equivalent wheel load λ i damage-equivalent factor representing spectrum / cycle e ff ects φ fat fatigue dynamic factor for vertical wheel actions φ 2 dynamic factor on hoist load when hoisting an unrestrained grounded load in regular operation φ 5 dynamic factor for horizontal actions from drives (acceleration / deceleration) ∆ σ stress range ∆ σ C fatigue strength at the reference number of cycles (detail category / FATclass) D Palmgren–Miner damage sum n j applied number of cycles at level j N j allowable number of cycles to failure at level j (from S–N curve) Nomenclature Q e = φ fat λ i Q max , i , (1)